Dynamic response of deep buried tunnels in saturated soil to effect of seismic acceleration

By establishing and solving the dynamic control equations for circular tunnels in saturated soil to the effect of the seismic acceleration, the general solution is obtained. According to the geometrical equation and physical equation for the elastic mechanics problem, the stress and strain expressions in the saturated soil and tunnel structure are deduced. Based on a circular tunnel in saturated soil under the action of earthquake acceleration boundary conditions, the numerical calculation is carried out, and the influences of seismic frequency, tunnel structure parameters and seismic acceleration on the seismic response of the circular tunnel in saturated soil are comprehensively analyzed. The results show that, with the increase of the earthquake frequency, the pore water pressure and the maximum values of stress components decrease. The pore water pressure and the maximum values of stress components increase when the tunnel lining structure shear modulus increases. The effect of the seismic acceleration on the pore water pressure and stress component is the most obvious, and the increase ratio of earthquake acceleration and the increase multiples of stress components are basically the same. With the increase of the distance away from the tunnel, the pore water pressure, radial stress component and tangential stress component decrease obviously, and the shear stress component is large and has slow attenuation. These results are very helpful for correctly understanding the seismic performance, damage mechanisms and seismic design of tunnels.